Practical C++ Design (eBook)

Adam B. Singer graduated first in his class at the Georgia Institute of Technology in 1999 with a bachelors degree in chemical engineering. He subsequently attended the Massachusetts Institute of Technology on a National Defense, Science, and Engineering Graduate Fellowship. He graduated from MIT with a Ph.D. in chemical engineering in 2004 after defending his thesis titled Global Dynamic Optimization. Since graduation, Adam has been a member of the research and engineering staff at an oil and gas major, where he has worked in software development, design, and project management in areas such as optimization, reservoir simulation, decision support under uncertainty, basin modeling, well log modeling, and stratigraphy. He has also served on and chaired committees designing in-house training in the areas of technical software development and computational and applied mathematics. He currently holds a research supervisory position.Adam additionally held the title of adjunct assistant professor in the Department of Computational and Applied Mathematics at Rice University from 2007-2012. In both 2006 and 2007, he taught a graduate level course, CAAM 520, on computational science. The course focused on the design and implementation of high performance parallel programs.

Table of Contents 5
About the Author 11
About the Technical Reviewer 12
Preface 13
Chapter 1: Defining the Case Study 19
1.1 A Brief Introduction 19
1.2 A Few Words About Requirements 20
1.3 Reverse Polish Notation 21
1.4 The Calculator’s Requirements 23
1.5 The Source Code 24
Chapter 2: Decomposition 26
2.1 The Elements of a Good Decomposition 27
2.2 Selecting an Architecture 29
2.2.1 Multi-Tiered Architecture 29
2.2.2 Model-View-Controller (MVC) Architecture 31
2.2.3 Architectural Patterns Applied to the Calculator 32
2.2.4 Choosing the Calculator’s Architecture 33
2.3 Interfaces 34
2.3.1 Calculator Use Cases 35
2.3.1.1 Use Case: User Enters a Floating Point Number onto the Stack 35
2.3.1.2 Use Case: User Undoes Last Operation 35
2.3.1.3 Use Case: User Redoes Last Operation 35
2.3.1.4 Use Case: User Swaps Top Stack Elements 35
2.3.1.5 Use Case: User Drops the Top Stack Element 36
2.3.1.6 Use Case: User Clears the Stack 36
2.3.1.7 Use Case: User Duplicates the Top Stack Element 36
2.3.1.8 Use Case: User Negates the Top Stack Element 36
2.3.1.9 Use Case: User Performs an Arithmetic Operation 36
2.3.1.10 Use Case: User Performs a Trigonometric Operation 37
2.3.1.11 Use Case: User Performs yx 37
2.3.1.12 Use Case: User Performs 37
2.3.1.13 Use Case: User Loads a Plugin 37
2.3.2 Analysis of Use Cases 38
2.3.3 A Quick Note on Actual Implementation 44
2.4 Assessment of Our Current Design 45
2.5 Next Steps 45
Chapter 3: The Stack 47
3.1 Decomposition of the Stack Module 47
3.2 The Stack Class 50
3.2.1 The Singleton Pattern 50
3.2.2 The Stack Module as a Singleton Class 52
3.2.2.1 The Pimpl Idiom 54
3.3 Adding Events 56
3.3.1 The Observer Pattern 57
3.3.1.1 Enhancing the Observer Pattern Implementation 58
3.3.1.2 Handling Event Data 63
3.3.2 The Stack as an Event Publisher 68
3.3.3 The Complete Stack Interface 69
3.4 A Quick Note on Testing 70
Chapter 4: The Command Dispatcher 72
4.1 Decomposition of the Command Dispatcher 72
4.2 The Command Class 73
4.2.1 The Command Pattern 73
4.2.2 More on Implementing Undo/Redo 74
4.2.3 The Command Pattern Applied to the Calculator 76
4.2.3.1 The Command Interface 76
4.2.3.2 The Undo Strategy 85
4.2.3.3 Concrete Commands 90
4.2.3.4 An Alternative to Deep Command Hierarchies 91
4.3 The Command Repository 96
4.3.1 The CommandRepository Class 96
4.3.2 Registering Core Commands 102
4.4 The Command Manager 103
4.4.1 The Interface 103
4.4.2 Implementing Undo and Redo 104
4.5 The Command Dispatcher 106
4.5.1 The Interface 107
4.5.2 Implementation Details 108
4.6 Revisiting Earlier Decisions 110
Chapter 5: The Command Line Interface 112
5.1 The User Interface Abstraction 112
5.1.1 The Abstract Interface 113
5.1.2 User Interface Events 116
5.1.2.1 Command Data 117
5.1.2.2 User Interface Observers 118
5.2 The Concrete CLI Class 120
5.2.1 Requirements 120
5.2.2 The CLI Design 122
5.2.2.1 The Interface 122
5.2.2.2 The Implementation 123
5.3 Tying It Together: A Working Program 127
Chapter 6: The Graphical User Interface 129
6.1 Requirements 129
6.2 Building GUIs 132
6.2.1 Building GUIs in IDEs 133
6.2.2 Building GUIs in Code 134
6.2.3 Which GUI Building Method Is Better? 135
6.3 Modularization 136
6.3.1 The CommandButton Abstraction 136
6.3.2 The CommandButton Design 137
6.3.3 The CommandButton Interface 141
6.3.4 Getting Input 143
6.3.5 The Design of the InputWidget 143
6.3.6 The Interface of the InputWidget 145
6.4 The Display 146
6.4.1 The Design of the Display Class 148
6.4.2 A Poor Design 148
6.4.3 An Improved Display Design 149
6.5 The Model 150
6.6 The Display Redux 152
6.7 Tying It Together: The Main Window 153
6.8 Look-and-Feel 155
6.9 A Working Program 156
6.10 A Microsoft Windows Build Note 158
Chapter 7: Plugins 159
7.1 What Is a Plugin? 159
7.1.1 Rules for C++ Plugins 160
7.2 Problem 1: The Plugin Interface 163
7.2.1 The Interface for Discovering Commands 163
7.2.2 The Interface for Adding New GUI Buttons 168
7.2.3 Plugin Allocation and Deallocation 170
7.2.4 The Plugin Command Interface 170
7.2.5 API Versioning 173
7.2.6 Making the Stack Available 174
7.3 Problem 2: Loading Plugins 175
7.3.1 Platform-Specific Plugin Loading 176
7.3.2 Loading, Using, and Closing a Shared Library 176
7.3.3 A Design for Multi-Platform Code 178
7.3.3.1 The Obvious Solution: Libraries 179
7.3.3.2 Raw Preprocessor Directives 179
7.3.3.3 (Slightly) More Clever Preprocessor Directives 180
7.3.3.4 A Build System Solution 181
7.3.3.5 A Platform Factory Function 182
7.3.3.6 An Abstract Factory for Generalized Platform Independent Code 186
7.4 Problem 3: Retrofitting pdCalc 191
7.4.1 Module Interfaces 192
7.4.1.1 Source Code Hiding 192
7.4.1.2 DLL Hiding 193
7.4.1.3 Implicit or Documentation Hiding 195
7.4.1.4 Module Design for pdCalc 195
7.4.2 Adding Plugin Buttons to the GUI 196
7.5 Incorporating Plugins 197
7.5.1 Loading Plugins 198
7.5.2 Injecting Functionality 199
7.6 A Concrete Plugin 201
7.6.1 Plugin Interface 201
7.6.2 Source Code Dependency Inversion 203
7.6.3 Implementing HyperbolicLnPlugin’s Functionality 204
7.7 Next Steps 207
Chapter 8: New Requirements 208
8.1 Fully Designed New Features 208
8.1.1 Batch Operation 209
8.1.2 Stored Procedures 210
8.1.2.1 The User Interface 212
8.1.2.2 Changes to the Command Dispatcher 213
8.1.2.3 Designing the StoredProcedure Class 217
8.1.2.4 The Composite Pattern 218
8.1.2.5 A First Attempt 219
8.1.2.6 A Final Design for the StoredProcedure Class 221
8.2 Designs Toward a More Useful Calculator 224
8.2.1 Complex Numbers 224
8.2.1.1 Modifying Input and Output 225
8.2.1.2 Modifying the Stack 227
8.2.1.3 Modifying Commands 229
8.2.2 Variables 229
8.2.2.1 Input and New Commands 230
8.2.2.2 Number Representation and the Stack 231
8.2.2.3 The Symbol Table 232
8.2.2.4 A Trivial Extension: Numeric Constants 233
8.2.2.5 Functionality Enabled by Variables 233
8.3 Some Interesting Extensions for Self-Exploration 234
8.3.1 High DPI Scaling 234
8.3.2 Dynamic Skinning 234
8.3.3 Flow Control 235
8.3.4 An Alternative GUI Layout 235
8.3.5 A Graphing Calculator 235
8.3.6 A Plugin Management System 236
8.3.7 A Mobile Device Interface 236
Appendix A: Acquiring, Building, and Executing pdCalc 237
A.1 Getting the Source Code 237
A.2 Dependencies 237
A.3 Building pdCalc 238
A.3.1 Using Qt Creator 239
A.3.2 Using the Command Line 240
A.4 Executing pdCalc 241
A.4.1 Using Qt Creator 241
A.4.2 Using the Command Line 241
A.5 Troubleshooting 242
Appendix B: Organization of the Source Code 245
B.1 The src Directory 245
B.1.1 The pdCalc Directory 245
B.1.2 The pdCalc-simple-cli Directory 246
B.1.3 The pdCalc-simple-gui Directory 246
B.1.4 The utilities Directory 246
B.1.5 The backend Directory 246
B.1.6 The cli Directory 247
B.1.7 The gui Directory 248
B.1.8 The plugins Directory 248
B.2 The test Directory 248
B.2.1 The testDriver Directory 249
B.2.2 The utilitiesTest Directory 249
B.2.3 The backendTest Directory 249
B.2.4 The cliTest Directory 250
B.2.5 The guiTest Directory 250
B.2.6 The pluginsTest Directory 250
References 251
Index 254